PHPで開発した中古リサイクルサイトに購入履歴閲覧機能を実装

<a href="purchase_records.php">购买记录</a>

// 连接数据库
$conn = new mysqli("localhost", "username", "password", "database");

// 验证登录状态
session_start();
if (!isset($_SESSION["user_id"])) {
  header("Location: login.php"); //用户未登录，跳转到登录页面
  exit;
}

// 查询用户的购买记录
$user_id = $_SESSION["user_id"];
$sql = "SELECT * FROM purchase_records WHERE user_id = '$user_id'";
$result = $conn->query($sql);

<table>
  <tr>
    <th>购买记录ID</th>
    <th>商品名称</th>
    <th>购买日期</th>
    <th>购买价格</th>
  </tr>
  <?php while ($row = $result->fetch_assoc()) { ?>
    <?php
      $product_id = $row["product_id"]; 
      $product_sql = "SELECT name FROM products WHERE id = '$product_id'";
      $product_result = $conn->query($product_sql);
      $product_row = $product_result->fetch_assoc();
      $product_name = $product_row["name"];
    ?>
    <tr>
      <td><?php echo $row["id"]; ?></td>
      <td><?php echo $product_name; ?></td>
      <td><?php echo $row["purchase_date"]; ?></td>
      <td><?php echo $row["price"]; ?></td>
    </tr>
  <?php } ?>
</table>